

const regexp = /^[\d]{11}$/;

console.log( regexp.test( '1234567890' ) );
console.log( regexp.test( '12345678901' ) );
console.log( regexp.test( '123456789012' ) );
console.log( regexp.test( 'renli123douhonghong' ) );
console.log( regexp.test( '0xABCDEF123' ) );